This invention relates to communications networks and, in particular, to a novel service capable network designed to meet the requirements of modern users of communications services and to permit the opportunity for communications service growth.
Communications networks have historically been constructed using models and protocols as guides. Networking models and protocols have proliferated over the past few years as new networks have been introduced or existing networks have evolved to accommodate new end-user, device and application requirements. The proliferation of networking models has been manifested in monolithic, highly integrated network and network component architectures. Functionality and products developed for a target group of end-users, devices or applications are almost invariably not readily extendible to another network without extensive modification or complete re-creation. New networks cannot capitalize on functionality and protocols developed for previous networks because monolithic integrated designs do not permit porting. Current networks provide limited choice of services and the choices available are often difficult to access. Adding functionality to current networks requires complex modifications of existing functionality. The time required to do these modifications is incompatible with modern competitive communications business environment where the speed to market greatly influences total revenues earned.
Modern voice communications networks have evolved in the twentieth century with a focus on creating universal telephone services. Currently, a revolution in telecommunications is underway that holds the promise of providing ubiquitous service for multimedia applications. Modern networks are in need of an enabling interoperability infrastructure, just as in the past computers were in the need of a data network. It is widely recognized that networking solutions need to take into account increasingly more powerful edge devices and content services that are currently available or are under development.
Others have recognized this need and contributed to the design of network architectures aimed at providing ubiquitous access to multimedia services. For example, the Telecommunications Information Networking Architecture Consortium (TINA-C) have produced a document entitled Service Architecture Version: 5.0 dated Jun. 16, 1997. The TINA-C architecture stems from a guiding principle arising from market, industry and sociological trend analysis. The key trends analyzed in devising the architecture include: layering the network architecture to move application and service logic out of transport nodes and specific telecommunications technologies to higher level entities; providing telecommunications in a multi-player, multi-provider environment; and, user choice of telecommunication services. The TINA-C architecture is a three macro-layer view of the network that assumes a middleware distributed processing environment, and utilizes an Open Distributed Processing (ODP) environment similar to that defined by the Object Management Group (OMG). The TINA-C architecture advocates technology independent views of transport elements and connections by representing both abstractly. It also includes the concept of a communications broker used to match communication services in the middle layer and transport layers with user specifications. Communications can be effected across federated, heterogeneous networks and conversion occurs at network edges as a part of the Resource Partition Layer. The Conversion, referred to as adaptation is an automated process which may not be user selected.
Another network architecture was proposed by the MultiMedia Communications Forum, Inc. in a paper entitled Reference Architecture Model Specifications dated 1995. The purpose of the document is to provide a framework for the structure of the integrated services required by distributed multimedia applications. The focus is on the aspects of the architectural model that support multimedia communication applications such as multimedia conferencing and multimedia information service. The underlying technology is not of primary focus. The MMCF architectural framework consists of logical domains which offer a set of services and their respective functions. The partitioning addresses the complex problem of communicating between distributed application processes. Each domain is accessed by functions in other domains through an open interface referred to as an Application Program Interface (API) The open interface shields each domain from the specific (characteristics,of the functions and services provided by other domains. Thus, the specification of domains may evolve with changing technology without directly impacting other domain specifications. Within this model resides a manager entity, associated with the application, middleware, media device and transport domains to manage information flow sent/received from the network and delivered to the end-user.
The MMCF reference architecture model consists of a user presentation layer, an application domain layer, a middleware domain layer, and a lower layer which is divided into a media device domain sector and a transport domain sector. APIs are provided between each of the four layers to enable inter-layer communications. Communications are handled in a trickle-down, trickle-up format in which direct communication appears to be enabled only between adjacent layers. User applications must therefore traverse each intervening layer in order to initiate a communication session regardless of the simplicity of the user""s requirement. This leads to complication in network infrastructure and contributes to costs and decreases efficiency.
There therefore exists a need for a layered service capable network which enables access to each respective layer in the network from a network edge or from an adjacent layer in order to ensure the flexibility required to satisfy the communications requirements of a diverse community of users and to permit efficient inter-working of federated networks. There also exists a need for a layered network having layers that may be utilized as self-standing entities and owned by separate business entities.
It is an object of the invention to provide a service capable network based on a layered network model in which layers of functionality are clearly separated.
It is a further object of the invention to provide a service capable network model in which brokers act on behalf of user applications or adjacent networks to find acceptable service offerings on demand.
It is yet a further object of the invention to provide a service capable network in which primitives that reflect natural, recurrent communications needs are used to provide simple network interfaces to exploit network-provided capabilities.
It is a further object of the invention to provide a service capable network in which network functionality is partitioned into transport path independent functions, transport path associated functions and functions in a direct line of the path.
It is a further object of the invention to provide a service capable network in which content adaptation transforms either or both of the presentation and transport aspects of encoded content format without requiring detailed knowledge of its meaning.
It is yet a further object of the invention to provide a service capable network in which conditioning provides bi-directional conversions between representations when entering or exiting the network.
It is yet a further object of the invention to provide a service capable network in which the brokers take user service and policy information communicated through primitives and use the information to select a service provider for a communication session.
It is yet a further object of the invention to provide a service capable network in which proxy clients augment conditioning by creating primitives from content and connectivity information to permit brokers to be employed.
It is yet a further object of the invention to provide a service capable network in which the brokers may be matching brokers or negotiating brokers.
It is another object of the invention to provide a service capable network in which directory services enable user and device tracking to permit the accommodation of mobile, transient and stationary users.
The invention therefore provides a service capable communications network for enabling communications between sources and sinks, comprising:
a first logical layer for providing network functions, the first logical network layer being partitioned into multi-nodal services which may be accessed by users, user agents or adjoining networks using a first set of primitives which permit interaction with the first logical network layer functionality to initiate and control the multi-nodal services;
a second logical layer for providing node functions, the second logical layer being partitioned into nodal services which may be accessed by users, user agents, the first logical network layer multi-nodal services or adjoining networks using a second set of primitives which permit interaction with the second logical layer functionality to initiate and control communication paths and support transport functionality; and
the first and second logical layers have a recursive layer structure.
The first and second logical layers of the service capable network (SCN) in accordance with the invention are respectively referred to as the xe2x80x9cenhanced services layerxe2x80x9d and the xe2x80x9cprimary services layerxe2x80x9d. The enhanced and the primary services layers have a recursive layer structure. As used in this document, xe2x80x9crecursive network layer structurexe2x80x9d means a substantial duplication of functionality between logical layers in the network, the duplication being limited only to an extent required to adapt to differences in functionality in respective network layers. The SCN functionality is further partitioned into transport path independent functions; transport path associated functions; and functions in a direct line of the path. Partitioning communications services into functions as they relate to path maximizes flexibility and accommodates diversity of network layer ownership. The functionality is further partitioned into edge-related and non-edge-related categories. Successful partitioning permits independent businesses to evolve and operate around aspects of functionality, if so desired.
In the SCN, user applications or adjacent networks may use brokers to isolate posted service offerings that satisfy their communication needs. As a communication session is established, the brokers complete sections of an electronic contract which is preferably presented to the user application by the user-facing service provider. The electronic contract governs the communication session and stipulates the compensation owed to the service provider(s) involved in the transport of the payload, as well as any service provider(s) involved in related services such as conditioning or conversions of payload data.
The SCN also supports mobile, transient and stationary users and devices using directory services which store user and device profiles that permit any user or device in the network to be located.